TY - JOUR

T1 - Numerical computation of human interaction with arbitrarily oriented superquadric loop antennas in personal communications

AU - Chen, Wen Tzu

AU - Chuang, Huey Ru

N1 - Funding Information:
Manuscript received June 4, 1997; revised March 16, 1998. This work was supported in part by the National Center for Highspeed Computing and the National Science Council of the Republic of China under Grants NCHC-86-03-011 and NSC 87-2218-E-006-054. The authors are with the Department of Electrical Engineering, National Cheng Kung University, Tainan, Taiwan, 70101 R.O.C. Publisher Item Identifier S 0018-926X(98)04872-8.

PY - 1998

Y1 - 1998

N2 - Loop antennas are widely used in many personal communication systems such as radio pagers. This paper presents results from an extensive numerical simulation of the human interaction with loop antennas. The loop antenna with a superquadric curve, which is able to model the circular, ellipse, square, and rectangular loop is used to model the rectangular loop antenna with rounded corners. The magnetic frill source is used to model the antenna feeding structure. A realistically shaped full-scale human-body model (1.7 m) is constructed. The coupled integral equations (CIE) approach, which consists a Pocklingtontype integral equation (PIE) for the loop antenna and a volume electric field integral equation (VEFIE) for the body with mutual coupling terms, are developed to numerically study this electromagnetic (EM) coupling problem. The method of moments (MoM) is employed for numerical solution. Numerical results for the antenna located at the chest pocket and waist-belt levels of the human body with arbitrary loop orientations are presented at 280-MHz VHP paging band. The pager's internal rectangular loop antenna with rounded corners is modeled by a superquadric loop antenna. It is found that the real part of the impedance (radiation resistance) increases about five times and, hence, the antenna ohmic-loss radiation efficiency increases from 4% (in free-space) to 33, 17, and 26% for the x-, y-, and z-oriented loops when proximate to the body. The radiation efficiencies, reduced by the body absorption effect, are 13, 40, and 27% for the x-, y-, and z -oriented loops, respectively. For the j/-oriented loop, which is found to be the most suitable for radio-paging communications, it has the highest value of Eg average power gain (product of the directive gain and the ohmic-loss and bodyabsorption efficiencies) in the horizontal plane. The computed antenna characteristics influenced by the human body, including the input impedance, antenna patterns, cross-polarization field level, radiation efficiencies, and maximum/minimum and average power gains, are very useful for the antenna/RF design and the link budget consideration of the personal communication systems.

AB - Loop antennas are widely used in many personal communication systems such as radio pagers. This paper presents results from an extensive numerical simulation of the human interaction with loop antennas. The loop antenna with a superquadric curve, which is able to model the circular, ellipse, square, and rectangular loop is used to model the rectangular loop antenna with rounded corners. The magnetic frill source is used to model the antenna feeding structure. A realistically shaped full-scale human-body model (1.7 m) is constructed. The coupled integral equations (CIE) approach, which consists a Pocklingtontype integral equation (PIE) for the loop antenna and a volume electric field integral equation (VEFIE) for the body with mutual coupling terms, are developed to numerically study this electromagnetic (EM) coupling problem. The method of moments (MoM) is employed for numerical solution. Numerical results for the antenna located at the chest pocket and waist-belt levels of the human body with arbitrary loop orientations are presented at 280-MHz VHP paging band. The pager's internal rectangular loop antenna with rounded corners is modeled by a superquadric loop antenna. It is found that the real part of the impedance (radiation resistance) increases about five times and, hence, the antenna ohmic-loss radiation efficiency increases from 4% (in free-space) to 33, 17, and 26% for the x-, y-, and z-oriented loops when proximate to the body. The radiation efficiencies, reduced by the body absorption effect, are 13, 40, and 27% for the x-, y-, and z -oriented loops, respectively. For the j/-oriented loop, which is found to be the most suitable for radio-paging communications, it has the highest value of Eg average power gain (product of the directive gain and the ohmic-loss and bodyabsorption efficiencies) in the horizontal plane. The computed antenna characteristics influenced by the human body, including the input impedance, antenna patterns, cross-polarization field level, radiation efficiencies, and maximum/minimum and average power gains, are very useful for the antenna/RF design and the link budget consideration of the personal communication systems.

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U2 - 10.1109/8.686768

DO - 10.1109/8.686768

M3 - Article

AN - SCOPUS:0032099421

VL - 46

SP - 821

EP - 828

JO - IEEE Transactions on Antennas and Propagation

JF - IEEE Transactions on Antennas and Propagation

SN - 0018-926X

IS - 6

ER -